1. Field of the Invention
The present invention relates to saw blades such as circular saw blade, band saw blade and the like. More specifically, the invention relates to a saw blade in which the cutting force is further weakened so that the life of a body section of the saw blade is improved.
2. Description of the Related Art
Conventionally, the saw blade generally has a structure which includes an unset tooth which is not set to a left-and-right direction viewed from a cutting direction of the saw blade, and left and right set teeth which are set to the right-and-left direction. In order to improve an ejection characteristic of chips generated at the time of cutting a workpiece and prevent a phenomenon that the saw blade is caught in a cutting groove of the workpiece, the width should be generally set to be larger so that a gap between an inner face of the cutting groove and a body section side face of the saw blade becomes large when the cutting groove is worked on the workpiece.
When a setting amount of the left and right set teeth is set to be large so that the set width becomes large as mentioned above, a burden on the unset tooth and the left and right set teeth increases, and thick chips which are approximately equal to the thickness of the respective teeth are generated. As a result, the ejection characteristic of the chips is deteriorated. Moreover, the left and right set teeth have a tendency to be bent greatly to the right-and-left direction and to be elastically deformed due to the component of force in the right-and-left direction at the time of cutting.
Therefore, a height difference is given to the dimensions of the plural saw teeth, and the set width of the set teeth with small height is set to be larger than the set width of the left and right set teeth with large height. As a result, a burden on the respective saw teeth is reduced and the chips are finely divided. With such a structure, abrasion of the saw teeth is reduced, and the life of the saw blade and the cutting characteristic can be improved.
However, when the set width is large, the bending of the set teeth to the right-and-left direction is large so that the set teeth are inclined greatly. When the chips S are generated continuously for a long time at the time of cutting the workpiece W, as schematically shown in FIG. 9, the chips have a tendency to flow to a direction which crosses the saw blade BS. As a result, the chips S easily enter a gap SL between the side face of the saw blade BS and an inner face of a cutting groove G and are easily caught, and the gap SL is easily clogged by the chips S. Therefore, there is a problem which should be improved further in the disposal of the chips. In this case, it is considered that a chip breaker be formed at the points of the respective saw teeth so as to cut the chips generated at the time of cutting a workpiece into pieces. However, the cut chips remain in a gullet of the saw blade, and it is undesirable that the chips cut into pieces in the gullet be again cut by the saw teeth.
Prior examples (e.g., Japanese Patent Application Laid-Open Nos. 6-716 and 6-717) disclose a curl forming section formed at the points of the saw teeth so as to curl the chips into a small spring shape considering the ejection characteristic and disposal characteristic of the chips generated at the time of cutting a workpiece.
In the prior saw blades, the set width of the saw blade is set to be large and the width of the cutting groove is set to be large so that the gap between the inner face of the cutting groove and the side face of the saw blade becomes large and the gap is prevented from being clogged by the chips.
Therefore, in the prior saw blades, as the set width of the saw blade is set to be larger, the bending of the set teeth is larger and their inclination becomes great. Moreover, an amount of the chips generated by cutting a workpiece is larger, and the whole cutting force becomes large so that a large force is created due to the body section of the saw blade. Further, even if the chips are curled, the chips have a tendency to gradually come to a sideways direction of the set teeth, namely, a direction of the gap between the side face of the saw blade and the inner face of the cutting groove due to the great inclination of the set teeth. Further, the chips have a tendency to be cut short due to chatter vibration at the time of the cutting. Therefore, the problem of the clogging due to the chips still remains, and the chip disposal after the cutting of workpieces and improvement of the life of the body section of the saw blade becomes problematic. Further, in the case where an expensive material is used, for example, there arises a problem of the material yielding when a lot of chips are generated.
The present invention has been achieved in order to solve the above problems. It therefore is an object of the present invention to provide a saw blade in which a cutting force is further weakened so that the life of a body section of the saw blade is improved.
To achieve the object, according to a first aspect of the present invention, there is provided a saw blade having an unset tooth and left and right set teeth which are set to a right-and-left direction, wherein when a thickness of a body section of the saw blade is D and a set width is T, a relationship T=D+2xcex1 is established; and wherein a relationship between the thickness D of the body section and the coefficient a is established in a manner such that when 0.85 mmxe2x89xa6Dxe2x89xa60.95 mm, 0.15 mmxe2x89xa6xcex1xe2x89xa60.35 mm is established; when 0.96 mm less than Dxe2x89xa61.2 mm, 0.2 mmxe2x89xa6xcex1xe2x89xa60.4 mm is established; when 1.2 mm less than Dxe2x89xa61.5 mm, 0.25 mmxe2x89xa6xcex1xe2x89xa60.43 mm is established; when 1.5 mm less than Dxe2x89xa61.7 mm, 0.3 mmxe2x89xa6xcex1xe2x89xa60.5 mm is established; and when 1.7 mm less than D, 0.35 mmxe2x89xa6xcex1xe2x89xa60.6 mm is established.
A second aspect of the invention provides a saw blade in which a small-diameter curl forming section for small curling chips generated at the time of cutting a workpiece is provided at a tip portion of saw teeth.
A third aspect of the invention provides a saw blade in which the small-diameter curl forming section has a plane rake face, which extends by a predetermined length from the point of the saw tooth to a direction of a gullet bottom section of the saw blade, and an arc-like curved face which is continuous to the rake face, in the case where a vertical line is drawn from a cross position between the curved face and a gullet forming curved face forming the gullet section towards a direction of the cutting by means of the saw teeth, a dimension from the vertical line to the point of the saw tooth is A, when a radius of the arc-like curved face is R, such that R/2xe2x89xa6Axe2x89xa62R, where R and A are in millimeters.
A fourth aspect of the invention provides a saw blade in which pitches of the saw teeth are unequal with each other.
A fifth aspect of the invention provides a saw blade having an unset tooth and left and right set teeth which are set to a right-and-left direction; and a small-diameter curl forming section for small curing chips generated at the time of cutting a workpiece at points of saw teeth, that pitches of the saw teeth are unequal with each other, and the small-diameter curl forming section has a plane rake face, which extends by a predetermined length B from the point of the saw tooth to a direction of a gullet bottom section of the saw blade, and an arc-like curved face having a radius R which is continuous to the rake face, and in the case where a vertical line is drawn from a cross position between the curved face and a gullet forming curved face forming the gullet section towards a direction of the cutting by means of the saw teeth, a dimension from the vertical line to the point of the saw tooth is A, a relationship that Axe2x89xa6R/2; Bxe2x89xa62 mm and 0.5 mmxe2x89xa6Rxe2x89xa63 mm is established.
According to the present invention, since the set width of the saw blade is set to be smaller than the set width of the prior saw blades, the width of the cutting groove of a workpiece becomes narrow. Moreover, the yielding of the workpiece is improved and an amount of the chips generated by the cutting becomes small so that post-processing becomes easy.
In addition, since the set width is set to be small, the whole cutting force becomes small, and the load which is put on the body section of the saw blade is reduced. As a result, the life of the body section can be improved, and noise at the time of the cutting can be reduced, and the accuracy of the cut section can be improved.
Further, since the small-diameter curl forming section having desirable shape is formed at the points of the saw teeth of the saw blade, the chips generated at the time of cutting a workpiece can be curled into a small-diameter spring form. As a result, the chips are prevented from being intertwined each other so that the ejecting characteristic can be improved. Therefore, although the set width of the saw blade is set to be small, the clogging due to the chips is prevented so that a workpiece can be cut.